[dns-operations] On server selection algorithms in dns resolvers

Robert Edmonds edmonds at mycre.ws
Tue Nov 24 18:31:53 UTC 2015

Edward Lewis wrote:
> I was mostly puzzled why they bothered to use 3 (and not 2) as the number
> of NS and A records.  This is why it stuck in my head.

    "Oh, I see. And most organizations only have two nameservers?"


    "Does that mean it's better? Is it any more reliable?

    "Well, it's one more nameserver, isn't it? It's not two. You see,
    most sysadmins, you know, will just have two nameservers. You're on
    two here, all the way up, all the way up, all the way up, you're got
    two nameservers serving DNS requests. Where can you go from there?

    "I don't know."

    "Nowhere. Exactly. What we do is, if we need that extra bit of
    reliability, you know what we do?"

    "Install a third one."

    "Three. Exactly. One more."

Robert Edmonds

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